Biomedical subjects

Moschos A Papadopoulos

Publications and source records attributed to Moschos A Papadopoulos.

11 recordsLinked to original sources

PubMed2006

Premolar root changes following treatment with the banded herbst appliance.

AIM: The aim of this prospective study was to radiographically assess root morphology changes in maxillary and mandibular premolars following Herbst appliance treatment. PATIENTS AND METHODS: Twenty-five consecutive adolescents (19 boys and six girls, mean age 13.08 years) with Class II, Division 1 malocclusion were treated with the banded Herbst appliance for a mean period of 13.16 months. Periapical radiographs of the upper and lower premolars were obtained before appliance insertion and immediately after appliance removal using the parallel technique. All radiographs were scanned, digitized and analyzed using appropriately adjusted cephalometric software. The pre- and post-treatment length and area of the first and second maxillary and mandibular premolar roots were calculated. Statistical analysis included paired t-tests to evaluate pre- and posttreatment changes, and independent t-tests to compare the pre and post-treatment differences between the first and the second premolars, which served as controls. The level of significance was set at p <or= 0.05 for all tests. RESULTS: No statistically significant decrease in premolar root lengths or areas was noted following removal of the Herbst appliance. We observed a statistically-significant decrease in the root area of the first mandibular premolars compared to that of the second mandibular premolars. CONCLUSIONS: Although we observed no statistically-significant root morphology changes in the first and second premolars following Herbst appliance treatment, the mandibular first premolars revealed significantly more root resorption than did the mandibular second premolars.

Adolescent↗

PubMed2006

Orthodontic journals with impact factors in perspective: trends in the types of articles and authorship characteristics.

INTRODUCTION: The purposes of this study were to analyze the types of articles and their authorship characteristics in the 3 orthodontic journals with impact factors--American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), Angle Orthodontist (AO), and European Journal of Orthodontics (EJO)--during 2 intervals of 5 years each (1993-1997 and 1998-2002) and to assess the changes in their contents during these periods. METHODS: The results of 3004 article entries were analyzed with the Pearson chi-square test, and the examination of the variability of the parameters studied among journals and across the 2 time intervals was performed at the 0.05 level of significance. RESULTS AND CONCLUSIONS: Significant differences were found between the journals with respect to the research component of articles (higher in the EJO) and case reports (higher in the AJODO and the AO). For each journal, differences were also identified between the 2 time intervals, with multi-authored papers and multiple affiliations appearing more frequently in the second interval. The contributions of articles from the United States and Canada to the AJODO and the AO were statistically higher than to the EJO. A similar trend was found for articles from Europe, which comprise more than 70% of the content of the EJO. An increased contribution of articles from East Asia and Oceania was noted in the second time interval, which reached almost 100% of the previous time frame. The potential sources of variation in the studied parameters are discussed.

Authorship↗

PubMed2006

Noncompliance unilateral maxillary molar distalization:.

The aim of this prospective study was the three-dimensional (3-D) analysis of tooth movements after unilateral upper molar distalization by means of a noncompliance intraoral appliance, the Keles slider. This appliance exerts a distalizing force of 150 g at approximately the level of the center of resistance of the upper first molar. Twelve patients (six girls and six boys with a mean age of 13.1 years) with a unilateral Class II molar relationship participated in the study. Dental casts were taken immediately before placement and after removal of the appliance. The casts were digitized using a 3-D surface laser scanner and superimposed on a predefined area of the palate. The average unilateral upper first molar distal movement was 3.1 mm (range: 2.4 to 5.3 mm). Anchorage loss was expressed by a 2.1 mm (range: 0.8 to 3.8 mm) proclination of the central incisors and a 6.1 degrees mesial inclination of the ipsilateral first premolar (range: 1.7 degrees to 12.3 degrees ). There was approximately 1 mm of midline deviation toward the contralateral side and a 1.6 mm (range: 0.8 to 2.3 mm) buccal displacement of the contralateral first premolar. A substantial variation was observed among patients. Noncompliance unilateral upper molar distalization was an efficient treatment approach. There was, however, a substantial anchorage loss. Case selection is strongly recommended because significant anterior crowding, ectopic canines, or spacing can lead to significant anchorage loss.

Adolescent↗

PubMed2006

Three-dimensional cephalometric evaluation of maxillary growth following in utero repair of cleft lip and alveolar-like defects in the mid-gestational sheep model.

OBJECTIVE: To evaluate maxillary growth following in utero repair of surgically created cleft lip and alveolar (CLA)-like defects by means of three-dimensional (3D) computer tomographic (CT) cephalometric analysis in the mid-gestational sheep model. METHODS: In 12 sheep fetuses a unilateral CLA-like defect was created in utero (untreated control group: 4 fetuses). Four different bone grafts were used for the alveolar defect closure. After euthanasia, CT scans of the skulls of the fetuses, 3D reconstructions, and a 3D-CT cephalometric analysis were performed. RESULTS: The comparisons between the operated and nonoperated skull sides as well as of the maxillary asymmetry among the experimental groups revealed no statistically significant differences of the 12 variables used. CONCLUSIONS: None of the surgical approaches used for the in utero correction of CLA-like defects seem to affect significantly postsurgical maxillary growth; however, when bone graft healing takes place, a tendency for almost normal maxillary growth can be observed.

Alveolar Process↗

PubMed2005

Dental arch and cephalometric changes following treatment for class III malocclusion by means of the function regulator (FR-3) appliance.

AIM: The aim of this retrospective clinical study was to evaluate dental arch, skeletal, dentoalveolar, and soft tissue profile changes following treatment of Class III malocclusion by means of the Function Regulator (FR-3) appliance. SUBJECTS AND METHODS: The study sample consisted of 14 growing patients (seven boys and seven girls) with a mean age of 9.7 +/- 1.1 years presenting Class III malocclusion. They were treated with an FR-3 appliance exclusively for a period of 2.4 +/- 0.6 years. Dental casts and lateral cephalometric radiographs were obtained immediately before initiation and after completion of treatment with the FR-3 appliance. Thirteen variables were used for the dental cast analysis and 61 variables for the cephalometric analysis. The paired t-test was utilized to evaluate the presence of significant changes (p < 0.05). RESULTS: The evaluation of the dental casts revealed that there was a significant increase in intermolar, interpremolar, and intercanine width of the maxilla and of palatal height after treatment. Concerning the mandible, an increase in intermolar and intercanine width and a decrease in lower arch depth were observed. Cephalometric evaluation revealed a significant decrease in SNB angle and an increase in ANB angle, overjet, facial convexity, nose prominence, and lower soft tissue face height. There was an increase in upper lip thickness and a decrease in lower lip convexity observed after treatment. CONCLUSIONS: The results of this study confirm a favorable functional and esthetic maxillary and mandibular position following treatment by means of the function regulator (FR-3) appliance.

Cephalometry↗

PubMed2005

Three-dimensional fetal cephalometry: an evaluation of the reliability of cephalometric measurements based on three-dimensional CT reconstructions and on dry skulls of sheep fetuses.

AIM: To develop a 3D CT cephalometric analysis for maxillary growth evaluation of sheep fetuses operated in utero, and to evaluate the reliability of this analysis by comparing it with a direct cephalometric analysis on dry skulls. MATERIAL AND METHODS: Five skulls of operated sheep fetuses were used, which after preparation were CT scanned and a 3D reconstruction was performed. A cephalometric analysis was performed directly on the dry skulls as well as on the reconstructed 3D CT images. In total, 56 linear distances were measured. In order to access the error of the method, the procedure was repeated after a 2 week interval. RESULTS: The comparison between the direct cephalometric and the 3D CT analysis revealed that only 5 variables were significantly different. The evaluation of the error of method revealed that 7 variables of the direct cephalometric analysis and none of the 3D CT analysis differed significantly. CONCLUSIONS: According to the results of this study, it can be concluded that a cephalometric analysis on 3D CT reconstructed images of the skulls includes fewer identification errors and seems to be an accurate and reliable method that could be regarded at least as equivalent to conventional cephalometry.

Animals↗

PubMed2005

Efficiency of noncompliance simultaneous first and second upper molar distalization: a three-dimensional tooth movement analysis.

Objective of this prospective study was the three-dimensional (3D) analysis of tooth movements after the noncompliance simultaneous distalization of the first and second maxillary molars. Ten patients (five girls and five boys; mean age: 13.2 years) with bilateral Class II molar relationships were treated with a noncompliance, fixed intraoral appliance. Upper second molars had already erupted in all cases. Dental casts and lateral cephalometric radiographs were taken immediately before placement and after removal of the appliance. The casts were 3D digitized and superimposed on a predefined area in the palate. The resulting holograms, as well as the cephalometric radiographs, were digitized and analyzed by means of customized cephalometric software. The whole procedure was repeated after a two- to four-week interval to estimate the error of both methods. The cast assessment of 3D sagittal and vertical tooth movements was more reliable than the cephalometric record. The average maxillary first molar distal movement was 2.8 mm. Anchorage loss was expressed by a 1.9-mm proclination of the central incisors. A substantial variation among patients and among the right and left side in the same patient was observed. Noncompliance simultaneous distalization of the first and second maxillary molars can be an efficient treatment option for the correction of Class II molar relationship. However, anchorage loss and individual variation have to be seriously considered. Bilaterally symmetrical effectiveness should not be relied upon.

Adolescent↗

PubMed2004

Cephalometric changes following simultaneous first and second maxillary molar distalization using a non-compliance intraoral appliance.

AIM: The aim of this prospective study was to evaluate the dentoalveolar, skeletal and soft tissue changes induced by a modified minimal-compliance intraoral appliance following the simultaneous distalization of first and second maxillary molars. SUBJECTS AND METHODS: The study sample consisted of 14 patients with a mean age of 13.4 years treated by one clinician. In all cases a bilateral Class II molar relationship was corrected to Class I in a mean treatment period of 16.5 weeks. Lateral cephalometric analysis of the sample was based on the radiographs taken before and immediately after treatment with the appliance. The mean maxillary first molar distal movement was 1.4 mm, accompanied by a mean distal tipping of 6.8 degrees. The vertical change in molar position was insignificant. The anchorage unit was unable to completely resist the reciprocal mesial force of the activated coil spring. The second premolars were moved mesially by a mean 2.6 mm and tipped by a mean 4.1 degrees without significant extrusion. The mean increase in overjet was 0.9 mm, and the mean decrease in overbite 1.0 mm. RESULTS: The results of this study have shown that the presented intraoral appliance is an effective and reliable means of distalizing first and second maxillary molars simultaneously without the need for patient compliance. Appliance effects are limited primarily to the dentoalveolar structures. Mesial movement and slight protrusion of the anchorage unit have to be taken seriously into consideration during intraoral distalization.

Activator Appliances↗

PubMed2004

Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the mid-gestational sheep model.

AIM: The success of intrauterine surgery in treating non-life-threatening malformations such as myelomeningocoele, has also renewed strong interest in using this technique for treating craniofacial malformations. Nevertheless, the only experimental cleft-like defect models known, are those concerning wound healing of soft tissues. MATERIAL AND METHODS: Attempts were made to repair artificial cleft-like defects including transplantation of 11 autogenous foetal bone grafts from the iliac crest or ulna, and were randomly assigned to three study groups, using the mid-gestational sheep model. In a 4th study group, lyophilized collagen, a bone-regenerating bioresorbable implant material, was used to fill the alveolar defect. RESULTS: In all groups, there was a slight degree of asymmetry and thinning of the lip. Radiological studies demonstrated a variable degree of abnormality of the maxilla, ranging from none to a mild deviation. Three-dimensional computer tomography, two-dimensional maximal intensity projection findings, and histological analysis confirmed bony healing of the alveolar cleft-like defect. DISCUSSION/CONCLUSION: Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the sheep is feasible. This is a reliable and valuable model toward a possible clinical application for intrauterine treatment of clefts.

Absorbable Implants↗

PubMed2004

Nickel content of as-received and retrieved NiTi and stainless steel archwires: assessing the nickel release hypothesis.

This study assesses the nickel content of as-received and retrieved stainless steel and NiTi archwires alloys. New and used brand-matched, composition-matched, and cross section-matched archwires were subjected to scanning electron microscopy and energy-dispersive electron probe microanalysis. Elemental analysis was performed on three randomly selected areas, and the nickel content, expressed as ratios of Ni/Ti (in NiTi wires) or Ni/Fe (in stainless steel), was statistically analyzed with a t-test (alpha = .05). No changes were detected with respect to Ni content ratios between as-received and retrieved NiTi or stainless steel wires, suggesting an absence of nickel release. Wear and delamination phenomena on the wire surface and the formation of galvanic couple between the stainless steel wires and bracket brazing materials intraorally may modify the corrosion susceptibility of the wire alloys in clinical conditions.

Corrosion↗

PubMed2002

Three-dimensional craniofacial reconstruction imaging.

This review article aims to describe and discuss the imaging techniques most commonly used in medicine and dentistry to obtain three-dimensional images of the craniofacial complex. Three-dimensional imaging techniques provide extensive possibilities for the detailed and precise analysis of the whole craniofacial complex, for virtual (on-screen) simulation and real simulation of orthognathic surgery cases on biomodels before treatment, as well as for the detailed evaluation of the effects of treatment. Laser scanning in combination with the stereolithographic biomodeling seems to be a very promising combination for three-dimensional imaging, although there is still considerable room for improvement. Constant efforts should be made in the direction of developing and enhancing the existing techniques as well as exploring the potential for developing new methods based on emerging sectors of technology.

Cephalometry↗